Salmonella Enteritidis predominance determined by serotyping and real-time PCR in poultry-derived food and avian isolates

Abstract

This study aimed to determineSalmonella entericasubspeciesentericaserovar Enteritidis (SE) presence by conventionalserotyping and SE-specific real-time PCR (SE-rPCR) in poultry-derived food and avian isolates in our laboratorySalmonellaspp.collection. Conventional serotyping indicated that 32 (8 chicken meat, 10 egg, 14 avian) out of 56 (57%) isolates were SE, whereas 8 (3chicken meat, 2 turkey meat, 3 avian) (14%) isolates were serogroup B, 6 (1 chicken meat, 1 egg, 4 avian) (11%) were serogroup C1, 4(3 chicken meat, 1 turkey meat) (7%) were serogroup C2-C3, 4 (3 chicken meat, 1 turkey meat) (7%) were serogroup E4, and 2 (avian)(4%) isolates were categorized as nonserogrouped/nonserotyped. Thirty-three (8/18 chicken meat, 10/11 egg, 15/23 avian) out of 56(59%)Salmonellaisolates were positive by SE-rPCR. SE was determined as the most prevalent serotype in both of the tests regardlessof the sample type. Conventional serotyping and SE-rPCR results were in agreement in all but 1 isolate. Considerably high relativeaccuracy (98%), sensitivity (100%), and specificity (96%) with almost perfect agreement between the two methods (Cohen s kappa =0.96) indicated SE-rPCR as a reliable tool in the rapid identification of SE isolates to complement conventional serotyping.